State of charge indicator of hybrid vehicle

ABSTRACT

A state of charge indicator includes a first indication unit that provides an indicator display within a predetermined display range including first and second ends, according to an increase/decrease in a state of charge of a battery of a hybrid vehicle. In an EV traveling mode, the first indication unit allows the first and second ends to correspond respectively to an upper limit of a state of charge range directed to the EV traveling mode, and a first threshold that defines switching from the EV traveling mode to an HV traveling mode. In the HV traveling mode, the first indication unit allows the first and second ends to correspond respectively to a second threshold that defines switching from the HV traveling mode to the EV traveling mode, and a lower limit of a state of charge range directed to the HV traveling mode.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority from Japanese Patent ApplicationNo. 2015-032488 filed on Feb. 23, 2015, the entire contents of which arehereby incorporated by reference.

BACKGROUND

The technology relates to an SOC indicator that provides an indicationof an SOC of a hybrid vehicle having an EV traveling mode.

An engine-electric motor hybrid vehicle (HV) includes an engine and amotor generator as power sources for traveling, allowing for motorassistance on occasions such as acceleration by using electric power.The electric power may be generated in association with use of aregeneration brake, etc. and charged in a battery.

In recent years, such a hybrid vehicle is further provided with afunction of charging from an external power supply such as a domesticpower supply and a commercial power supply, attaining expansion of arange of usability of an electric vehicle (EV) traveling mode thatallows for traveling with sole use of the motor generator without usingthe engine. This type of hybrid vehicle has been spreading as a plug-inhybrid vehicle (PHEV).

The plug-in hybrid vehicle as mentioned above may include a secondarybattery such as, but not limited to, a lithium ion battery and a nickelhydrogen battery, as power storage to accumulate electric power to beused in traveling.

In such a secondary battery, a ratio of residual electric power tochargeable electric power (total capacity) is called a state of charge(SOC).

In the plug-in hybrid vehicle, SOC control (charge and dischargecontrol) of the battery may differ as follows between the EV travelingmode that involves traveling with sole use of the motor generator and anHV traveling mode with combined use of the engine and the motorgenerator.

In the EV traveling mode, in many cases, traveling may be started in arange of a relatively high SOC (almost full-charged); when the SOCdecreases to the extent that continuation of the EV traveling modebecomes difficult, the EV traveling mode may be switched to the HVtraveling mode.

In contrast, in the HV traveling mode, the SOC control may be targetedto a relatively low SOC state; within a relatively narrow SOC range,charge (e.g., regenerative power generation) and discharge (motor drive)may be repeated with high frequency.

The plug-in hybrid vehicle as mentioned above may include an SOCindicator (a battery residual capacity indicator) in order to presentinformation on residual capacity of the battery to a driver.

As one example of existing techniques concerning such an SOC indicator,Japanese Patent (JP-B) No. 5223822 describes a residual capacityindicator that changes display colors of a bar graph in accordance witha first traveling mode and a second traveling mode. The first travelingmode gives priority to traveling with sole use of a motor. The secondtraveling mode involves use of an internal combustion engine and thegenerator.

JP-B No. 5223822 also provides a description that, in the display in thefirst traveling mode, the bar graph is color-divided at a positioncorresponding to residual capacity where the first traveling mode isswitched to the second traveling mode.

Although the existing technique as mentioned above enables a grasp of acurrent SOC, it provides a driver with little information on a timingwhen the traveling mode will be returned to the EV traveling mode again,in a case of recovery of an SOC by charging such as regenerative powergeneration in traveling in the HV traveling mode. Hence, it is difficultto forecast switching of traveling modes.

Moreover, the HV traveling mode generally involves repetitive charge anddischarge within a relatively narrower SOC range than that of the EVtraveling mode. However, in the existing technique as mentioned above,an SOC indication is regularly performed on a scale of a full SOC range.Thus, charge and discharge in the HV traveling mode may only causeminute fluctuation within a narrow range in the SOC indication, leadingto difficulties for a driver in grasping SOC transition.

SUMMARY

It is desirable to provide an SOC indicator of a hybrid vehicle thatallows for an intuitive grasp of a change of traveling modes in responseto a change in SOC and SOC transition in each traveling mode.

An aspect of the technology provides an SOC indicator including a firstindication unit that provides an indicator display within apredetermined display range including a first end and a second end, inaccordance with an increase and a decrease in an SOC of a battery of ahybrid vehicle. The first indication unit allows, in an EV travelingmode, the first end to correspond to an upper limit of an SOC rangedirected to the EV traveling mode, and allows the second end tocorrespond to a first threshold that defines switching from the EVtraveling mode to an HV traveling mode, in which the EV traveling modegives priority to driving with sole use of an electric motor, and the HVtraveling mode involves driving with combined use of an engine and theelectric motor, and controlling charge and discharge of the battery toallow the SOC to be within a prescribed range. The first indication unitallows, in the HV traveling mode, the first end to correspond to asecond threshold that defines switching from the HV traveling mode tothe EV traveling mode, and allows the second end to correspond to alower limit of an SOC range directed to the HV traveling mode.

In the SOC indicator, the first indication unit may provide anindication of a minimum of the indicator display in the EV travelingmode, prior to the switching from the EV traveling mode to the HVtraveling mode. The first indication unit may provide an indication of amaximum of the indicator display in the HV traveling mode, prior to theswitching from the HV traveling mode to the EV traveling mode.

The SOC indicator may further include a second indication unit thatprovides an indication of the SOC. The second indication unit mayinclude a movable index and a fixed index. The movable index may bemovable in accordance with the increase and the decrease in the SOC, andmay be movable between positions corresponding to a maximum and aminimum of an SOC range directed to the EV traveling mode and the HVtraveling mode. The fixed index is disposed along a movement range ofthe movable index.

In the SOC indicator, the fixed index may include: a first sign thatindicates a position corresponding to the first threshold; and a secondsign that indicates a position corresponding to the second threshold.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a schematic configuration of a power trainand relevant parts of a hybrid vehicle including an SOC indicatoraccording to an implementation of the technology.

FIG. 2 illustrates a pointer SOC meter in the SOC indicator according tothe implementation.

FIG. 3 illustrates an SOC indication, in an EV traveling mode, on an MFDin the SOC indicator according to the implementation.

FIG. 4 illustrates an SOC indication, in an HV traveling mode, on theMFD in the SOC indicator according to the implementation.

FIG. 5 illustrates one example of SOC transition and switching operationof traveling modes in the hybrid vehicle according to theimplementation.

FIG. 6 illustrates one example of transition of the SOC indication onthe pointer SOC meter and the MFD in the SOC indicator according to theimplementation.

DETAILED DESCRIPTION

An implementation of the technology may involve expanding an indicationof an SOC range substantially to an entire region of a display range ofa bar graph display. The SOC range may be directed to each of an EVtraveling mode and an HV traveling mode.

In the following, some implementations of the technology are describedin detail with reference to the drawings.

An SOC indicator of a hybrid vehicle (hereinafter simply referred to asan “SOC indicator”) according to an implementation may be provided in anengine-electric motor hybrid vehicle that may be, for instance, anautomobile such as, but not limited to, a passenger car, and may have aplug-in charging function and an EV traveling mode. The EV travelingmode involves traveling mainly with sole use of a motor.

FIG. 1 is a block diagram of a schematic configuration of a power trainand relevant parts of a hybrid vehicle including the SOC indicatoraccording to the implementation.

Referring to FIG. 1, the vehicle may be an engine-electric motor hybridAWD vehicle including, for example, an engine 10, a torque converter 20,an engine clutch 30, a steering reverser 40, a variator 50, an outputclutch 60, a front differential 70, a rear differential 80, a transferclutch 90, a motor generator 100, an engine controller 210, atransmission controller 220, a motor generator controller 230, a hybridintegrated controller 240, a battery 300, a charger 310, a combinationmeter 410, and a multi-function display (MFD) 420.

The engine 10 may be an internal combustion engine used as a powersource for traveling of the vehicle, together with the motor generator100.

As the engine 10, for instance, a four-stroke gasoline engine may beused.

The engine 10 may include a main body and auxiliaries. The main body andthe auxiliaries may be controlled by the engine controller 210. Theengine 10 may generate output torque corresponding to request torquespecified by the hybrid integrated controller 240, based on, forexample, an accelerator operation by a driver.

The torque converter 20 may be a fluid coupling that transmits an outputof the engine 10 to the engine clutch 30.

The torque converter 20 may serve as a starting device that allows fortransmission of engine torque in a stop state of the vehicle.

The torque converter 20 may be controlled by the transmission controller220, and may include an undepicted lock-up clutch that directly couplesinput side (impeller side) and output side (turbine side).

The engine clutch 30 may be provided between the torque converter 20 andthe steering reverser 40, allowing for connection and disconnection of apower transmission route therebetween.

For instance, the engine clutch 30 may be disengaged in response to aninstruction from the transmission controller 220 on occasions such as,but not limited to, the EV traveling mode. In the EV traveling mode, thevehicle travels with sole use of an output of the motor generator 100.

The steering reverser 40 may be provided between the engine clutch 30and the variator 50, allowing for switching between an advance mode anda retreat mode in response to an instruction from the transmissioncontroller 220. The advance mode may involve direct coupling of thetorque converter 20 and the variator 50. The reverse mode may involvereversing a rotation output of the torque converter 20 and transmittingthe reversed rotation output to the variator 50.

The steering reverser 40 may include, for instance, a planetary gearset.

The variator 50 may be a transmission mechanism that continuouslychanges a rotation output of the engine 10 and a rotation output of themotor generator 100. The rotation output of the engine 10 may betransmitted from the steering reverser 40.

The variator 50 may be, for instance, a chain type continuously variabletransmission (CVT) including a primary pulley 51, a secondary pulley 52,and a chain 53.

The primary pulley 51 may be provided on input side of the variator 50in driving of the vehicle, i.e., on output side in regenerative powergeneration. The primary pulley 51 may be supplied with the rotationoutputs of the engine 10 and the motor generator 100.

The secondary pulley 52 may be provided on output side of the variator50 in driving of the vehicle, i.e., on input side in regenerative powergeneration.

The secondary pulley 52 may be adjacent to the primary pulley 51 andturnable around a rotation axis that is parallel to a rotation axis ofthe primary pulley 51.

The chain 53 may be annularly formed and wound around the primary pulley51 and the secondary pulley 52, allowing for power transmissiontherebetween.

The primary pulley 51 and the secondary pulley 52 each may include apair of sheaves with the chain 53 interposed therebetween. The primarypulley 51 and the secondary pulley 52 each may change an intervalbetween the pair of sheaves in response to transmission control by thetransmission controller 220, allowing for a continuous change in aneffective diameter.

The output clutch 60 may be provided between the secondary pulley 52 ofthe variator 50 and the front differential 70, and between the secondarypulley 52 of the variator 50 and the transfer clutch 90, allowing forconnection and disconnection of power transmission routes therebetween.

The output clutch 60 may be normally engaged in traveling of thevehicle, and may be disengaged in stopping of the vehicle on occasionssuch as, but not limited to, battery charge by driving the motorgenerator 100 with use of the output of the engine 10.

The front differential 70 may transmit, to right and left front wheels,driving force transmitted from the output clutch 60.

The front differential 70 may include a final reduction gear and adifferential mechanism. The differential mechanism absorbs a differencein rotation speeds of the right and left front wheels.

The output clutch 60 and the front differential 70 may be substantiallydirectly coupled to each other.

The rear differential 80 may transmit, to right and left rear wheels,driving force transmitted from the output clutch 60.

The rear differential 80 may include a final reduction gear and adifferential mechanism. The differential mechanism absorbs a differencein rotation speeds of the right and left rear wheels.

The transfer clutch 90 may be provided in the middle of a rear wheeldriving force transmission mechanism that transmits driving force fromthe output clutch 60 to the rear differential 80, allowing forconnection and disconnection of a power transmission route therebetween.

The transfer clutch 90 may be, for instance, hydraulic orelectromagnetic wet multiplate clutch that makes it possible tocontinuously change fastening force in engagement, i.e., transmissiontorque capacity.

The fastening force of the transfer clutch 90 may be controlled by thetransmission controller 220.

Changing the fastening force of the transfer clutch 90 may allow foradjustment of driving torque distribution to the front and rear wheels.

Also, the transfer clutch 90 may decrease or release the fastening forceto cause a slip, allowing for absorption of a difference in rotationspeeds of the front and rear wheels, when it is necessary to allow thedifference in the rotation speeds of the front and rear wheels inturning the vehicle or in executing control such as, but not limited to,anti-lock brake control or vehicle behavior control.

The transfer clutch 90 may transmit, to the motor generator 100 throughthe output clutch 60 and the variator 50, torque inputted fromrear-wheel side through the rear differential 80, etc. in energyregeneration by the motor generator 100.

The motor generator 100 may be a rotary electric machine that generatesthe driving force of the vehicle and performs energy regeneration byregenerative power generation with use of torque transmitted from wheelside in deceleration.

The motor generator 100 may be disposed concentrically with the primarypulley 51 of the variator 50.

The primary pulley 51 may be coupled to an undepicted rotor of the motorgenerator 100 through the rotation axis of the primary pulley 51.

As the motor generator 100, a permanent magnet synchronous motor may beused, for instance.

The motor generator 100 may have output torque in driving and an amountof regenerative energy (input torque) in regenerative power generationcontrolled by the motor generator controller 230.

The engine controller 210 may totally control the engine 10 and itsauxiliaries.

The transmission controller 220 may totally control parts such as, butnot limited to, the lock-up clutch of the torque converter 20, theengine clutch 30, the steering reverser 40, the variator 50, the outputclutch 60, and the transfer clutch 90.

The motor generator controller 230 may control characteristics such as,but not limited to, the output torque and the amount of regenerativeenergy of the motor generator 100.

The hybrid integrated controller 240 may integrally control parts suchas, but not limited to, the engine controller 210, the transmissioncontroller 220, and the motor generator controller 230 in response tothe request torque specified based on, for example, the accelerationoperation by a driver.

Each of these units may include an information processor such as a CPU,a memory such as a RAM and a ROM, an input output interface, and a busthat couples them to one another.

Also, these units may communicate with one another through acommunication system such as, but not limited to, a CAN communicationsystem, allowing for transmission of necessary information. The CANcommunication system is a kind of on-vehicle LAN system.

The hybrid integrated controller 240 may change traveling modes of thevehicle between the electric vehicle (EV) traveling mode and a hybridvehicle (HV) traveling mode based on an SOC as remaining electric energyof the battery 300.

The EV traveling mode may be a traveling mode that involves driving themotor generator 100 with use of power of the battery 300 and givespriority to traveling with sole use of the output of the motor generator100.

In the EV traveling mode, the engine 10 may be started to allow fortraveling with combined use of engine torque, only when driver requesttorque is large and it is difficult for the motor generator 100 tosolely generate sufficient torque.

Otherwise, the EV traveling mode may involve traveling of the vehiclewith sole use of the output of the motor generator 100 with the engineclutch 30 disengaged.

The HV traveling mode may be a traveling mode that involves traveling ofthe vehicle with combined use of the output torque of the engine 10 andthe motor generator 100.

The HV traveling mode may involve traveling of the vehicle with use ofthe output torque of the motor generator 100 when the driver requesttorque is small and there is a margin in the SOC; otherwise, the HVtraveling mode may involve traveling of the vehicle with use of theoutput torque of the engine 10.

Also, in a region where the driver request torque is large, the HVtraveling mode may involve traveling of the vehicle with combined use ofthe output torque of the engine 10 and the motor generator 100.

The hybrid integrated controller 240 may allow for automatic transitionto the HV traveling mode when, in the EV traveling mode, the SOC of thebattery 300 is lower than a predetermined first threshold.

Also, the hybrid integrated controller 240 may allow for automaticreturn to the EV traveling mode when, in the HV traveling mode, the SOCof the battery 300 exceeds a predetermined second threshold.

The motor generator controller 230 may supply the drive power to themotor generator 100 from the battery 300 in response to an instructionfrom the hybrid integrated controller 240.

The motor generator controller 230 may include, for example, an inverterand a converter. The inverter may AC-convert DC power supplied from thebattery 300, and may supply the AC-converted power to the motorgenerator 100. The converter may DC-convert AC power supplied from themotor generator 100, and may supply the DC-converted power to thebattery 300.

The battery 300 may be a power source or power storage that supplies themotor generator 100 with power for traveling.

As the battery 300, a secondary battery such as, but not limited to, alithium ion battery and a nickel hydrogen battery may be used, forinstance.

The battery 300 may include an SOC detector that detects the SOC, i.e.,a percentage of the remaining power to total capacity of the battery. Adetected SOC value may be transmitted to the hybrid integratedcontroller 240.

The battery 300 may be charged with, for instance, power generated bythe motor generator 100 on occasions such as, but not limited to, use ofa regenerative brake.

The battery 300 may further include a plug-in charging function thatallows for charging with an external power source.

The charger 310 may charge the battery 300 with use of power suppliedfrom an external power source such as, but not limited to, a domesticpower source and a commercial power source.

The charger 310 may include, for example, a connection device to theexternal power source, an AC-DC converter, and a transformer.

The combination meter 410 may be an instrument panel disposed in avehicle room and faced with a driver, for instance.

The combination meter 410 may include, for example, various instrumentssuch as, but not limited to, a speed meter, an engine tachometer, a fuelmeter, a water thermometer, and various indication lamps. Theinstruments and the indication lamps may be unitized in a commonhousing.

The combination meter 410 may include a pointer SOC meter 411 whosedescription is given below.

FIG. 2 illustrates the pointer SOC meter in the SOC indicator accordingto the implementation.

Referring to FIG. 2, the pointer SOC meter 411 may include a pointer 412and graduations 413 a to 413 i.

The pointer 412 may serve as a “movable index” in one implementation ofthe technology. The pointer 412 may be of a rotary type, and may beswayable within an angle range of, for instance, about 180°.

The pointer 412 may point one end of a movement range (e.g. upward in aninstance illustrated in FIG. 2) when the SOC of the battery 300 is apractical upper limit (e.g. 85%) in the EV traveling mode. The pointer412 may point another end of the movement range (e.g. downward in theinstance illustrated in FIG. 2) when the SOC is a practical lower limit(e.g. 15%) in the EV traveling mode and the HV traveling mode.

The graduations 413 a to 413 i may serve as a “fixed index” in oneimplementation of the technology. The graduations 413 a to 413 i may beprovided on a dial or a scale plate as a plate member disposed behindthe pointer 412 (or on farther side from a driver).

The graduations 413 a to 413 i may be disposed substantially along amovement locus of a tip of the pointer 412, from the one end to theother end of the movement range of the pointer 412, at substantiallyequal intervals in a discrete pattern. The movement locus may be shapedsubstantially as an arc with a central angle of 180°.

Near the uppermost graduation 413 a, a letter “F” may be provided as anindication of a substantially full-charged state.

Near the lowermost graduation 413 i, a letter “E” may be provided as anindication of emptiness of substantially available power.

The graduations 413 a to 413 i may be classified into a first group, asecond group, and a third group. The first group may include thegraduations 413 a to 413 e. The second group may include the graduations413 f and 413 g. The third group may include the graduations 413 h and413 i. These groups may be in different indication modes, e.g. indifferent indication colors from one another.

For one instance, the first group, the second group, and the third groupmay be respectively color-coded in green, light blue, and blue.

A region including the graduations 413 a to 413 e of the first group mayprovide an indication of a region that involves executing solely the EVtraveling mode.

The pointer 412 may point the graduation 413 a as an indication of apractically full-charged state. As the SOC decreases, the pointer 412may turn counterclockwise to point the graduations 413 b, 413 c, 413 d,and 413 e sequentially.

A region including the graduations 413 f and 413 g of the second groupmay provide an indication of a region that involves executing possiblyboth the EV traveling mode and the HV traveling mode.

Specifically, in the EV traveling mode, when the SOC decreases and thepointer 412 points the region of the second group including thegraduations 413 f and 413 g, the EV traveling mode may be maintained.

In the HV traveling mode, when the SOC increases and the pointer 412points the region of the second group including the graduations 413 fand 413 g, the HV traveling mode may be maintained.

Here, the graduation 413 f may provide an indication of an automaticreturn line from HV to EV at which switching (or the automatic return)from the HV traveling mode to the EV traveling mode is performed. In theHV traveling mode, when the SOC increases to a value corresponding tothe graduation 413 f, a change from the HV traveling mode to the EVtraveling mode may be automatically performed. In one implementation ofthe technology, the automatic return line from HV to EV may serve as a“second sign”.

A region including the graduations 413 h and 413 i of the third groupmay provide an indication of a region that involves executing solely theHV traveling mode.

Here, the graduation 413 h may provide an indication of an automaticswitching line from EV to HV at which switching from the EV travelingmode to the HV traveling mode is performed. In the EV traveling mode,when the SOC decreases to a value corresponding to the graduation 413 h,a change from the EV traveling mode to the HV traveling mode may beautomatically performed. In one implementation of the technology, theautomatic switching line from EV to HV may serve as a “first sign”.

The combination meter 410 may include an undepicted indicator. Theindicator may be adjacent to the pointer SOC meter 411, and may providean indication of whether the current traveling mode is the EV travelingmode or the HV traveling mode by, for instance, lighting and extinctionof an icon.

The combination meter 410 may further include a predicted durationdistance indicator. The predicted duration distance indicator mayconstantly indicate a predicted duration distance in the EV travelingmode and a predicted duration distance with combined use of the EVtraveling mode and the HV traveling mode.

The MFD 420 may be an image display such as, but not limited to, an LCD.The MFD 420 may be disposed at a position to be viewed by a driver in avehicle room.

The MFD 420 may include, for instance, a group of a number of pixelsarranged in a matrix and variable in luminance and display colors,allowing any text or graphics to be displayed within its range ofresolution.

The MFD 420 may be disposed, for instance, in a center region in avehicle widthwise direction of the instrument panel and near an upperend of the instrument panel.

The MFD 420 may have, in part of its display region, a function of SOCindication that provides, for instance, bar graph display of the SOC ineach of the EV traveling mode and the HV traveling mode.

The SOC indication on the MFD 420 may differ in indication modes asdescribed below, depending on whether the EV traveling mode or the HVtraveling mode is selected.

FIG. 3 illustrates the SOC indication, in the EV traveling mode, on theMFD in the SOC indicator according to the implementation.

The MFD 420 may provide the SOC indication in the form of a bar graphwhose length is variable in accordance with an increase or a decrease ofthe SOC. The bar graph may be superimposed on an illustration 421 of abattery.

In the EV traveling mode, as illustrated in FIG. 3, a bar graph 422 offull segment display may be displayed.

The bar graph 422 of the full segment display illustrated in FIG. 3 maybe displayed in, for instance, a rectangular shape. An upper end of thebar graph 422 may be substantially continuously raised and lowered byone pixel of the group of the pixels included in the MFD 420.

In accordance with the decrease in the SOC, the upper end of the bargraph 422 may be lowered, decreasing a length L of the bar graph 422.

FIG. 3 illustrates a non-limiting example of the bar graph 422 with itsupper end located on an upper end of a display range specified inadvance.

At this occasion, the SOC of the battery 300 may be the practical upperlimit (e.g. 85%) of the SOC use range in the EV traveling mode.

When the SOC decreases to reach the switching line from the EV travelingmode to the HV traveling mode (refer to FIG. 5 to be described later),the length of the bar graph 422 may become substantially zero, and thebar graph 422 may disappear on the MFD 420. In other words, only theillustration 421 may remain displayed on the MFD 420.

FIG. 4 illustrates the SOC indication, in the HV traveling mode, on theMFD in the SOC indicator according to the implementation.

In the HV traveling mode, a plurality of (e.g. eight) segments 423 a to423 h may be displayed in a sequential arrangement from top to bottom.The plurality of segments 423 a to 423 h may be superimposed on theillustration 421 of the battery.

In the HV traveling mode, the SOC may be indicated by the number of thesegments displayed.

All of the segments 423 a to 423 h may be displayed near the SOC upperlimit (the automatic return line from the EV traveling mode) in the HVtraveling mode. As the SOC decreases, the segments 423 a to 423 h maydisappear sequentially from the uppermost segment 423 a.

When the SOC becomes near the lower limit in the HV traveling mode, allthe segments 423 a to 423 h may disappear. In other words, only theillustration 421 may remain displayed.

Here, the bar graph 422 of the full segment display and the segments 423a to 423 h of the 8-segment display may be provided in differentindication modes such as, but not limited to, colors and luminance.

For instance, the bar graph 422 may be displayed in green, and thesegments 423 a to 423 h may be displayed in blue.

The hybrid integrated controller 240 may perform calculation processingof an SOC value for the full segment display at any time. The SOC valuefor the full segment display may be used in the pointer SOC meter 411and in the full segment display in the MFD 420.

The hybrid integrated controller 240 may also perform calculationprocessing of an SOC value for the 8-segment display. The SOC value forthe 8-segment display may be used in the 8-segment display in the MFD420.

The calculated SOC values may be received and subjected to displayprocessing by ECUs included in the pointer SOC meter 411 and in the MFD420.

The ECU of the MFD 420 may further receive a flag of determination onoperation of the EV traveling mode and the HV traveling mode, and mayperform switching between the full segment display (in the EV travelingmode) and the 8-segment display (in the HV traveling mode). The flag ofdetermination on operation of the EV traveling mode and the HV travelingmode may be outputted from the hybrid integrated controller 240.

Description is given below on SOC transition of the battery 300 andswitching operation of traveling modes in accordance with a change inthe SOC, in a hybrid vehicle according to an implementation.

FIG. 5 illustrates one instance of the SOC transition and switchingoperation of traveling modes, in the hybrid vehicle according to theimplementation.

In FIG. 5, a vertical axis denotes the SOC of the battery 300, and ahorizontal axis denotes time.

In FIG. 5, the SOC may be, for instance, about 85% at a point A,corresponding to a practically full-charged state of the battery 300.

When traveling in the EV traveling mode is started at the state of thepoint A, the SOC may gradually decrease in accordance with passage oftraveling time, although the SOC may be temporality recovered byregenerative power generation, etc. Power consumption due to traveling,use of electrical components, or other factors may usually exceed anamount of the regenerative power generation in braking, or any otherpower generation.

When the SOC passes a point B and a point C sequentially, and decreasesto a level of a point D, the hybrid integrated controller 240 mayautomatically perform switching from the EV traveling mode to the HVtraveling mode. The point B may correspond to the automatic return linefrom HV to EV. The point C may correspond to the upper limit of anordinary use range of HV. The point D may correspond to the automaticswitching line from EV to HV.

The automatic switching line from EV to HV may be set in a region where,for instance, the SOC substantially coincides with SOC control center inthe HV traveling mode.

The automatic return line from HV to EV may be set in a region where,for instance, the predicted duration distance in the EV traveling modeafter the return to the EV traveling mode is equal to or larger than aprescribed value.

In the HV traveling mode, the hybrid integrated controller 240 mayperform charge and discharge control to allow the SOC of the battery 300to be between a level corresponding to the point C and a levelcorresponding to a point E. The point C may be the upper limit of theordinary use range of HV. The point E may be a lower limit of theordinary use range of HV.

There may be cases that the SOC falls below the lower limit of theordinary use range of HV for some reason such as, but not limited to,insufficient opportunities of regenerative power generation. In suchcases, when the SOC reaches a level corresponding to a point F as amotor-traveling unallowable level, motor traveling may become difficult.Further, when the SOC reaches a level corresponding to a point G as alower limit of a battery use range, the hybrid integrated controller 240may drive the motor generator 100 with use of the output of the engine10 to allow for power generation, performing control to charge thebattery 300 to prevent the SOC from further decreasing.

FIG. 6 illustrates one instance of transition of the SOC indication ofthe pointer SOC meter and the MFD in the SOC indicator according to theimplementation.

In FIG. 6, columns A to G respectively correspond to the points A to Gin FIG. 5 as described above.

The pointer SOC meter 411 may maintain a common indication mode over allof the columns A to G, and may provide the SOC indication solely by apositional change or sway of the pointer 412.

In a state of the column A, the pointer 412 may point the graduation 413a that indicates the full-charged state.

The pointer 412 may start here to turn counterclockwise in accordancewith the decrease in the SOC. In a state of the column B, the pointer412 may point the graduation 413 f that indicates the automatic returnline from the HV traveling mode to the EV traveling mode.

In a state of the column C, the pointer 412 may point the graduation 413g that indicates the upper limit of the ordinary use range of HV.

In a state of the column D, the pointer 412 may point the graduation 413h that indicates the automatic switching line from the EV traveling modeto the HV traveling mode.

At this occasion, a driver may forecast, based on how the pointer 412comes close to the graduation 413 h, switching from the EV travelingmode to the HV traveling mode.

With a further decrease in the SOC, in states of the columns E and F,the pointer 412 may shift toward the graduation 413 i. In a state of thecolumn G, the pointer 412 may point the graduation 413 i.

In a case of an increase of the SOC, the pointer 412 may turn clockwiseto point a position corresponding to the current SOC.

The SOC indication on the MFD 420 in the state of the column A (in theEV traveling mode) may be the full segment display as illustrated inFIG. 3, where the length or height of the bar graph 422 may be at itsmaximum.

The length of the bar graph 422 may start here to decrease continuouslywith the decrease in the SOC. The bar graph 422 may disappear in thestate of the column D as the automatic switching line from the EVtraveling mode to the HV traveling mode.

In a case of automatic switching from the EV traveling mode to the HVtraveling mode, prior to the switching, the bar graph 422 may be set todisappear for a prescribed period.

When switching from the EV traveling mode to the HV traveling mode isperformed, the SOC indication on the MFD 420 may be changed to the8-segment display illustrated in FIG. 4.

In the state of the column D, i.e. immediately after the switching tothe HV traveling mode, the segments 423 e to 423 h may be displayed. Atthis occasion, the segments 423 a to 423 d may disappear.

When the SOC starts here to decrease, the segment 423 e and the segment423 f may disappear sequentially. In the state of the column E, thesegments 423 g and 423 h may be displayed.

With a further decrease in the SOC, in the state of the column F, thesegment 423 g may disappear, and the segment 423 h may be displayed.

With a further decrease in the SOC, in the state of the column G, all ofthe segments 423 a to 423 h may disappear.

In the state of the column D, when the SOC increases due to regenerativepower generation, etc., the segments 423 d, 423 c, 423 b, and 423 a maybe sequentially displayed.

In the state of the column C, the segments 423 c to 423 h may bedisplayed.

In the state of the column B as the automatic return line from the HVtraveling mode to the EV traveling mode, all of the segments 423 a to423 h may be displayed.

In a case of the automatic return (switching) from the HV traveling modeto the EV traveling mode, prior to the switching, all of the segments423 a to 423 h may be set to be displayed for a prescribed period.

When the switching from the HV traveling mode to the EV traveling modeis performed, the SOC indication on the MFD 420 may be returned to thefull segment display, and a lower part of the bar graph 422 withone-third of its length may be displayed.

As described above, according to the implementation, in the SOCindication on the MFD 420, the SOC ranges directed to the EV travelingmode and the HV traveling mode are expanded to the entire display rangeof the bar graph 422. Hence, it is possible to easily grasp the SOCtransition in each traveling mode.

Moreover, in the EV traveling mode, the indication of the minimum of thebar graph 422 in which the bar graph 422 disappears means that a changeto the HV traveling mode is about to be made immediately thereafter(after an elapse of predetermined time). In the HV traveling mode, theindication of the maximum of the segments 423 a to 423 h in which all ofthe segments 423 a to 423 h are displayed means that a change to the EVtraveling mode is about to be made immediately thereafter (after anelapse of predetermined time). Hence, it is possible to easily grasp,based on the current indicator display, a possible timing of, forexample, switching of traveling modes.

Moreover, providing the pointer SOC meter 411 makes it possible toeasily grasp a relative state of the current SOC to total batterycapacity, regardless of the indication state of the MFD 420.

In addition, the pointer SOC meter 411 is provided with the graduationcorresponding to the traveling-mode switching (return) line. Hence, alsowith the pointer SOC meter 411, it is possible to easily grasp theswitching of traveling modes.

As described above, according to the implementation, it is possible toprovide an SOC indicator of a hybrid vehicle that allows for anintuitive grasp of a change of traveling modes in response to a changein SOC and SOC transition in each traveling mode.

(Modifications)

The technology is by no means limited to the implementations describedabove. The technology may be modified or altered in a variety of ways,and is intended to include such modifications and alterations.

First, configurations of a hybrid vehicle and an SOC indicator are notlimited to the implementations described above, and may be modified asappropriate.

For instance, in the foregoing description, described is oneimplementation in which the vehicle is a plug-in hybrid vehicle having aplug-in charging function. However, the technology may be applied to avehicle that has an EV traveling mode, i.e., a function of travelingwith sole use of a motor generator without starting an engine, even whenthe vehicle has no plug-in charging function.

Also, the engine is not limited to a gasoline engine as described in theforgoing implementation. A diesel engine or any other internalcombustion engine may be used.

Second, the pointer SOC meter in the forgoing implementation includes amechanical pointer and a scale plate. Instead, an image corresponding tosuch a pointer SOC meter may be displayed on an image display such as,but not limited to, an LCD.

Also, in the forgoing implementation, the three regions are providedwith graduations in the respective three colors. However, theintermediate region may be provided in gradation or in aseparately-colored pattern in a plurality of colors. In this case, oneend of the gradationed region, or one end of theseparately-colored-patterned region may serve as the automatic switchingline from EV to HV. Another end of the gradationed region, or anotherend of the separately-colored-patterned region may serve as theautomatic return line from HV to EV.

Third, the SOC indication on the MFD in the forgoing implementationinvolves the full segment display in the EV traveling mode and the8-segment display in the HV traveling mode. However, separate use ofplural segment display and the full segment display is not limited tothe forgoing implementation, and may be modified as appropriate.

For instance, the full segment display may be used in both the EVtraveling mode and the HV traveling mode. Alternatively, the pluralsegment display may be used in both the EV traveling mode and the HVtraveling mode.

Also, the number of segments in the plural segment display is notlimited to eight as in the forgoing implementation. The number ofsegments may be increased or reduced as appropriate.

Although some preferred implementations of the technology have beendescribed in the foregoing by way of example with reference to theaccompanying drawings, the technology is by no means limited to theimplementations described above. It should be appreciated thatmodifications and alterations may be made by persons skilled in the artwithout departing from the scope as defined by the appended claims. Thetechnology is intended to include such modifications and alterations inso far as they fall within the scope of the appended claims or theequivalents thereof.

The invention claimed is:
 1. A state of charge indicator for a state ofcharge (SOC) of a battery of a hybrid vehicle using traveling modesincluding an electric vehicle (EV) traveling mode giving priority todriving with a sole use of an electric motor, and a hybrid vehicle (HV)traveling mode involving driving with a combined use of an engine andthe electric motor and controlling charge and discharge of the batteryto allow the SOC to be within a prescribed range, the state of chargeindicator comprising: a first indication unit that provides an indicatordisplay within a predetermined display range including a first end and asecond end different from the first end in accordance with an increaseand a decrease in the SOC; and a controller that displays the SOC on thefirst indication unit, wherein the controller is configured to cause thestate of charge indicator to: display in a first display mode, on thefirst indication unit a range between an upper limit, corresponding tothe first end, of a state of charge range directed to the EV travelingmode, and a first threshold, corresponding to the second end, thatdefines a switching from the EV traveling mode to the HV traveling mode;display, in a second display mode, on the first indication unit a rangebetween a second threshold, corresponding to the first end, that is morethan the first threshold and defines a switching from the HV travelingmode to the EV traveling mode, and a lower limit, corresponding to thesecond end, of the state of charge range directed to the HV travelingmode; and switch between a first display mode and a second display modein accordance with the traveling modes, wherein the controller isfurther configured to cause the state of charge indicator to display onthe first indication unit an indication of a minimum of the indicatordisplay in the EV traveling mode for a predetermined period, prior tothe switching from the EV traveling mode to the HV traveling mode. 2.The state of charge indicator according to claim 1, wherein thecontroller is further configured to cause the state of charge indicatorto display on the first indication unit an indication of a maximum ofthe indicator display in the HV traveling mode for a predeterminedperiod, prior to the switching from the HV traveling mode to the EVtraveling mode, the maximum of the indicator display being differentfrom the minimum of the indicator display.
 3. The state of chargeindicator according to claim 1, further comprising a second indicationunit that provides an indication of the state of charge, the secondindication unit including a movable index and a fixed index, the movableindex being movable in accordance with the increase and the decrease inthe SOC, and being movable between positions corresponding to a maximumand a minimum of a state of charge range directed to the EV travelingmode and the HV traveling mode, and the fixed index being disposed alonga movement range of the movable index.
 4. The state of charge indicatoraccording to claim 2, further comprising a second indication unit thatprovides an indication of the state of charge, the second indicationunit including a movable index and a fixed index, the movable indexbeing movable in accordance with the increase and the decrease in theSOC, and being movable between positions corresponding to a maximum anda minimum of a state of charge range directed to the EV traveling modeand the HV traveling mode, and the fixed index being disposed along amovement range of the movable index.
 5. The state of charge indicatoraccording to claim 3, wherein the fixed index includes: a first signthat indicates a position corresponding to the first threshold; and asecond sign that indicates a position corresponding to the secondthreshold.
 6. The state of charge indicator according to claim 4,wherein the fixed index includes: a first sign that indicates a positioncorresponding to the first threshold; and a second sign that indicates aposition corresponding to the second threshold.
 7. The state of chargeindicator according to claim 1, wherein the indicator display displays astatus of a current use of one of the engine and the electric motorbetween the first threshold and the second threshold.
 8. The state ofcharge indicator according to claim 1, wherein the state of chargedecreases from the first end to the second threshold and from the secondthreshold to the first threshold.
 9. The state of charge indicatoraccording to claim 1, wherein the state of charge decreases from thefirst end to the second threshold.